Of all the psychoactive drugs, cannabis is the most widely used. Despite its illicit status the National Institute for Health have indicated that around 50 million Americans admit to having tried cannabis. Cannabis is related partly to cultural practices. In the West it is used predominantly for relaxation whilst in the Indian subcontinent for example, it is used as a work aid. Relatively recent statistics from the UK showed that of the 42,000 recorded drug offences each year around 40,000 of these were related to cannabis possession. The legal costs and manpower requirements involved seemed
disproportionate to the known effects of cannabis and in the UK last year, the government
recategorized cannabis as a class C drug. This means it is still an offence to possess cannabis but you can't be arrested as a result.

Previously negative attitudes of cannabis have begun to soften. This is turn has resulted in a more relaxed attitude over its perceived effects. In part this may be due to the focus on its therapeutic uses. The main active ingredient is delta-9-tetrahydrocannabinol (THC), with THC uptake being most efficient after smoking. THC is known to reduce fluid pressure in the eyeball and can relieve the symptoms of glaucoma. Cannabis also relieves nausea and can therefore be useful for cancer patients undergoing chemotherapy. Multiple Sclerosis sufferers have reported relief from their symptoms and research continues into the beneficial nature of the substance.

Cannabis can be smoked, eaten, or drunk as a form of tea. In low doses it leads to a relaxed mood state and in higher doses it may lead to euphoria. Not everyone experiences positive effects from cannabis and some novice users, or high dose regular users, have noticed increased anxiety or paranoia. THC also affects information processing and speed of response so anything that involves a skilled response (e.g. driving) can be negatively affected.

Smoking cannabis is no less harmful than smoking cigarettes. The cannabis leaf contains the same properties as tobacco and a fresh cannabis smoke can contain as much tar as twenty cigarettes. Tar is associated with cancers of the mouth, throat and lung in cigarette smokers. In pipe smokers tar is associated with cancer of the lips, gums and throat. With those who chew tobacco, tar is particularly associated with cancers of the jaw and gums.

Regular smokers of cannabis also risk the same problems of heart disease, cancer, respiratory and circulatory problems as any tobacco smoker. High use cannabis smokers often develop blood-shot eyes, caused by the dilation of blood vessels. There may also be an increased risk of mental health problems with users who have a family history of psychosis.

Most psychoactive drugs have both positive and negative effects. People clearly use drugs because of the positive effects but don't always know, or choose to overlook, the negative. It is therefore the ratio of positive to negative effects that fuels much of the drugs debate. For some people then, using cannabis is a better option than suffering, for others its use is more casual, but like any substance there is a potential price to pay in terms of the risks to health.